Highlighting in SolrNet

Question

I have a problem to get highlighting working. I use a ASP.Net MVC Application with a WCF Service. The WCF Service return the results to the view. My code is:

public IEnumerable<Dictionary<string, string>> SolrQuery(string searchString)
    {
        SolrInitialSetup(); 

        var solr = ServiceLocator.Current.GetInstance<ISolrOperations<SolrPDFDocument>>();

        var results = solr.Query(new SolrQueryByField("author", searchString),
            new QueryOptions
            {
                Highlight = new HighlightingParameters
                {
                    Fields = new[] { "search_snippet" },
                }
            });

        var returnedResults = new List<Dictionary<string, string>>();

        if (results.Count > 0)
        {
            foreach (var pdfDoc in results)
            {
                var docBuffer = new Dictionary<string, string>();
                docBuffer.Add("Id", ""+pdfDoc.Id.GetHashCode());
                docBuffer.Add("Content", "" + pdfDoc.Content.ElementAt(0));
                docBuffer.Add("Version", "" + pdfDoc.Version);

                foreach (var h in results.Highlights[results[0].Id])
                {
                    docBuffer.Add("search_snippet", String.Format("{0}", string.Join(", ", h.Value.ToArray())));
                    Debug.WriteLine("search_snippet", String.Format("{0}", string.Join(", ", h.Value.ToArray())));
                }
                returnedResults.Add(docBuffer);
            }
        }
        return returnedResults;
    }

@ Line foreach (var h in results.Highlights[results[0].Id]) I get an error in the browser The given key was not present in the dictionary. I have no idea whats wrong.

My schema.xml:

    <field name="id" type="string" indexed="true" stored="true" required="true" multiValued="false" /> 
    <field name="content" type="text_general" indexed="true" stored="true" multiValued="true" termVectors="true" termPositions="true" termOffsets="true"/>
    <field name="author" type="text_general" indexed="true" stored="true" termVectors="true" termPositions="true" termOffsets="true"/>
    <field name="_version_" type="long" indexed="true" stored="true"/>
    <field name="search_snippet" type="text_general" indexed="true" stored="true" termVectors="true" termPositions="true" termOffsets="true" />

My SolrPDFDocument.cs

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using SolrNet.Attributes;

namespace WcfSearchService
{
    class SolrPDFDocument
    {
        [SolrUniqueKey("id")]
        public string Id { get; set; }

        [SolrField("author")]
        public string Author { get; set; }

        [SolrField("content")]
        public ICollection<string> Content { get; set; }

        [SolrField("search_snippet")]
        public ICollection<string> SearchSnippet { get; set; }

        [SolrField("_version_")]
        public long Version { get; set; }
    }
}

My solrconfig.xml

<requestHandler name="/select" class="solr.SearchHandler">
    <!-- default values for query parameters can be specified, these
         will be overridden by parameters in the request
      -->
     <lst name="defaults">
       <str name="echoParams">explicit</str>
       <int name="rows">10</int>
       <str name="df">text</str>

     <!-- Highlighting defaults -->
       <str name="hl">on</str>
       <str name="hl.fl">search_snippet author content</str>
     </lst>
</requestHandler>

Answer 1

OK i have solved my problem.

Instead of using the sample code like that:

var results = solr.Query(new SolrQueryByField("author", searchString),
        new QueryOptions
        {
            Highlight = new HighlightingParameters
            {
                Fields = new[] { "author" },
            }
        });

I set the Parameter of the new Fields like this:

var results = solr.Query(new SolrQueryByField("text", searchString),
        new QueryOptions
        {
            Highlight = new HighlightingParameters
            {
                Fields = new[] { "*" },
            }
        });

So I'm getting all the snippets to all results. Thanks for your help!!!!

Answer 2

You might not be getting any highlight results at all. Can you debug your code and validate that results.Highlights is populated. Also check your highlighting defaults settings as I believe you need to set hl=true not on.

 <str name="hl">true</str>

Answer 3

This is interesting. For me, this wasn't working (I wasn't getting any results):

var results = solr.Query(new SolrQueryByField("text", searchString),
        new QueryOptions
        {
            Highlight = new HighlightingParameters
            {
                Fields = new[] { "*" },
            }
        });

But, this works for me:

 var results = solr.Query(string.Format("{0}:{1}", "text", searchString),
            new QueryOptions
            {
                Highlight = new HighlightingParameters
                {
                    Fields = new[] { "*" },
                }
            });

I am using solr 4.6.0 and SolrNet build #173 (16 Oct 13 00:32)